Thin Film Transistor Liquid Crystal Displays (TFT-LCDs) have the features of small volume, power saving and non-radiating and takes a leading role in the current flat-panel display market. Wide viewing angle display technologies have become a popular research topic nowadays.
Wide viewing angle displays are classified into the In-Plane Switching (IPS) type and the Advanced Super Dimension Switch (ADS) type according to the display mode. The IPS mode LCDs change the azimuth angle parallel to the substrate direction of the optical axis of the liquid crystal molecules by means of the transverse electric field generated by the pixel electrode and the common electrode in the same layer, thereby controlling the transmissivity. An IPS mode LCD can increase the viewing angle of the LCD up to 170°. However, there are the disadvantages of low contrast ratio and low transmissivity. As a result, the brightness of the backlight has to be increased to realize the display of images with high brightness.
An ADS mode LCDs form a multi-dimensional electric field (E-field) with both an E-field produced at edges of slit electrodes on the same plane and an E-field produced between a slit electrode layer and a plate electrode layer, so that liquid crystal molecules at all orientations, which are located directly above the electrodes and between the slit electrodes in a liquid crystal cell, can be rotated, which enhances the work efficiency of the liquid crystals and increases light transmittance. The ADS technology can improve the picture quality of the TFT-LCDs and has the advantages of high resolution, high transmissivity, low power consumption, wide viewing angles, high aperture ratio, low chromatic aberration, no push Mura, etc. With respect to different applications, variants of the ADS technology comprise high transmissivity I-ADS technology, high aperture ratio H-ADS technology and high resolution S-ADS technology and the like.
Whether for the IPS mode LCDs or for the ADS mode LCDs, the stronger the transverse E-field in the liquid crystal layer is, the higher the transmissivity is, and the lower the voltage required for driving the liquid crystal molecules to rotate to the same angle is. Currently, the IPS or ADS mode LCDs have low transmissivity and high driving voltage, which can jeopardize the display of high quality image by the LCDs.